Machine-switching telephone system



C. L. GOODRUM.

MACHINE SWITCHING TELEPHONE SYSTEM.

APPLICATIQN FILED JULY 14- 1917.

Patented May 24,1921.

UNITED STATES PATENT OFFICE CH ARIQES L. GOODRUM, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC" it COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATIQN OF NEW YORK.

MACHINE-SWITCHING TELEPHONE SYSTEM.

To all whom it may concern:

Be it known that I, CHARLES L. GooDRUM, a citizen of the United States, reslding at New York, in the county of New York and The object of the invention is to provide a common driving mechanism for a plurality of'equivalent line finder switches and for allotting an idle line finder switch for use.

Generally stated the invention comprises a group of equivalent finder switches of the usual two-motion step-by-step type and a driving mechanism, common to the group, arranged to automatically allot an idle finder switch for use and then to subsequently operate the individual vertical and rotary pawls of such allotted finder to establish aconnecv tion with a calling line.

In the drawing a diagrammatic view of a structure embodying this invention 1s shown,

together with an indicated calling subscribers substation and the necessary circuit arrangements for establishing a connection between the calling subscribers substation and a finder switch.

Referring to the drawing,- each finder switch comprises a shaft 1 which carries the brushes 2, 3 and 4, the vertical ratchet 5 and the rotary ratchet 6. The brushes are arranged to engagesubscribers line terminals in the terminal bank 8. Each shaft has cooperating therewith a vertical pawl 13, a

rotary pawl 1d and holding'pawls9 and 10 mounted on an armature 11 of a release magnet 12. i

The vertical pawls 13 of the finder switches are pivotally mounted on arms 17 which are loosely mounted on a rod 18. The rod is rotatably and longitudinally mounted in a support (not shown) and has spirally arranged thereon a number of cranks 20 each of which is arranged to engage a hole in one of the' arms 17. The cranks are so arranged that whenever the rod 18 is in its normal longitudinal position, one of the cranks is in engagement with its associate arm 17 so that if the Specification of Letters Patent. Patented May 24, 1921,

Application filed July 14, 1917. Serial No. 180,647.

rod is rotated, the vertical pawl attached to the engagedarm 17 is operated to raise the shaft of its associated switch. In order to allow another switch to be operated by the rod 18, the rod is first moved longitudinally.

to the left (as viewed in the drawing) by the attraction of the armature of magnet 42.

This movement of the rod is sufficient tomove the cranks away from the arms 17 which do not move with the rod when it is the opposite end of the rod 18 another ratchet.

wheel 25 is loosely mounted in such a manner that it is free to rotate'on the rod, but it moves longitudinally with the rod. Normally this ratchet wheel is engaged by a holding pawl 76, which is mounted on the frame (not shown), to prevent the wheel from rotating in a counter-clockwise direction. The ratchet wheel 25 is also normally engaged by an operating pawl 24 fastened to a collar 77 which is mounted on the rod in such a manner that it rotates with the rod, but does not I move longitudinally therewith. vBy this arrangement it will be seen that during the ver-,

tical operation of a finder switch the ratchet wheel 25 will be rotated in a clockwise direction-by'the pawl 24:. But as soon as the rod 18 is moved longitudinally the ratchet wheel disengages the pawls 24 and 7 6, the ratchet wheel is returned to its normal position bya" spring 26, one end of which is fastened to the ratchet wheel 25 and the other endis-fastened to the frame (not shown). This spring also serves to hold the rod 18 in its normal longitudinalposition.

A brush 27 is insulatedly mounted on the 5 ratchet wheel 25, and serves to hold the wheel in its normal position and also to keep spring 28 from engagement with spring 29 by normallyengaging the spring 28. During the rotation of the wheel by the pawl 24, the

brush engages contacts 30 for a purpose here inafter described.

The rotary pawls 14 of the switches are mounted on the arms 31 which are pivoted on a support (not shown). Each arm 31 has a lug 32 which projects downward and which is arranged to be engaged by a pair of pins 33 and 34 carried by a rod 35. These pairs to maintain the proper relation between the shafts 18 and 35 so'that the vertical and rotary 'pawls of the same finder switch willbe selected and operated, the two shafts are connected together by the gears 40 and 41. 7

It is believed that the invention will now be more readily understood by tracing a connection between a calling subscriber at substation A and a finder switch. It will be assumed that the apparatus is normally in the condition shown in the drawing, namely, the finder switch at'the left'of the drawing is the one allotted for use.

When the subscriber at substation A removes his receiver from the hook a circuit is completed from grounded battery, righthand-winding of relay 50, inner left-hand armature and back contact of relay 51, line conductor 52, telephone'apparatus of substation A, line conductor 53, back contact andouterlefthand armature of relay 51, left-hand winding of relay to ground. Relay 50' then becomes energized and completes a circuit from grounded battery, winding of relay' 54, left-hand armature and back contact of relay 55, conductor 56, contact spring 57 and its back contact 58,

' conductor 59, contact spring 60, left-hand armature and front contact of relay 50, back contact and outer left-hand armature of relay 51, left hand winding of relay 50 to ground. Relay 54 becomes energized and at its left-handarmature and front contact completes a locking circuit for itself to conductor 56- and ground over the circuit previously described. Relay 54 at its outer right-hand armature and front contact connects ground to contact 30, which is individual to the group of lines with which the calling line is associated. At its inner right-'hand'armature and front contact, relay 54 completes a circuit from grounded battery, winding of relay 55, front contact and inner armature of relay 54 to ground.

7 Relay 55 becomes energized and connects over conductor ,61. Relay :72 by attracting its armature produces a break in the energizing circuit of the release magnet 12. The grounding of conductor 61 also. completes a circuit from grounded battery, winding of relay 65, conductor. 64, contact springs 63 and 62 to ground over conductor 61. The energization of relay 65 establishes a break in conductor 7 8. A circuit is also completed at this time from grounded battery, winding of primary magnet 23, contact springs 69 and 68, conductor 67, side-switch arm 66, contact springs 63 and 62 to ground over conductor 61. tracting its armature rotates the rod 18, thereby causing the arm 17 of the allotted switch to move the pawl'13 into engagement with the vertical ratchet 5. The shaft 1 is thereby moved upward so that the brushes 2, 3 and 4 are placed in operative relation to the first group of contacts in the bank 8. Gnly a slight rotation of the rod 18 is produced due to the arm 17 engaging the stop 79, but this rotation is sufficient to move the brush 27 into engagement with the first contact 30, in which position it is held by the pawl 76 engaging the. ratchet wheel 25. As soon as-primary magnet 23 denergizes the rod 18 is returned to its normal position by spring 15 fastened to arm'17. Since primary magnet 23 opens contact springs 68 and 69 each time it is energized, a stepping circuit is produced, thereby causing the brush shaft 1'to be moved upward step by step over the various groups. This vertical movement of brush shaft 1 continues untilto ground. Escape magnet 7 3 becomes energized andmoves tliQSiClG-SWitClifLl-IHS into position 2. The escape magnet lOGIIIgLSlOW to release is held energized until a circult is closed therefor wh n the side-switch arm 74 reaches its second position: from grounded battery, winding of escape magnet 73', sideswitch arm 74 in second position, side-- switch arm 66 in second position, contact springs 63 and 62 to ground over conductor 61. An energizing circuit is closed for secondary magnet 87 grounded battery, winding of magnet 87, contact springs 84 and 85, conductor 86, side-switch arm 66, contact springs 63 and 62 to ground over conductor61. Y i

The secondary magnet 87 by attracting;

its armature moves the rod 35 longitudinally, thereby causing'th-e arm'31 and the pawl 14 of the allotted switch to be operated to rotate the shaft 1 so that the brushes 2, 3 and 4 engage, the first set of contacts in the Primary magnet 23- by at-- selected group.- As soon as the secondary magnet becomes denergized the rod 35 returned to its normal longitudinal position by spring 96. The secondary magnet byattracting its armature opens contact springs 84 and'85. Thusit isintermittently energizecl'and deenergized to move the brushes 2, 3 and 4 step by step from one set of c'on- 'tacts to the next until the terminals ofthe calling line are reached, at which time a circuit is completed from grounded battery, winding of cut-off relay 5'1 conductor 88,

in conductor 78 to complete a circuit from grounded batter left-hand winding of magnet 42, con uctor .100, armatureand back contact of relay 65, conductor 78,brush 36, contact 37, conductor 104, contact springs 95 and 96 (closed upon the first verticalstep of the shaft '1) to ground. Magnet-'42 by attracting its armature moves rod.:18 longitudinally, therebymoving. the crank 20 out of engagement'with "arm 17 of the last used switch, and also ratchet wheel 25 out of engagement With paWls 24 and '76. The ratchet wheel is then returned to its normal position by spring 26. In order to assure the ratchet wheel25 reaching itsnormal position before magnet 42 deenergizes, a look ing circuit for magnet 42 is completedfrom grounded battery, right-hand winding of magnet 42, contact springs 105 and 106,

conductor 107, contact springs 28 and 29 to ground. As soon as the ratchet "wheel reaches its normal position, brush 28separa'tes contact"springs 28 and29and'opens this locking circuit.

NThe deenergization of relay "also completes a circuit from grounded batterv,w1nding'of allottermagnet 38, contact springs and 81, conductor 83, armature-and :back

contact of relay 65 and conductor 78, brush 36, contact 37, conductor 104, contactsprings and 96 to ground. Magnet 38 becomes energized and by operating'pawl 102 rotates the rods 35 and 18 so that th'ey are in'a'position to operate the next finder switch, but if this finder switch is busy, ground will be found upon terminal-37 associated therewith, which Will cause the magnet 38 to again energize androtate the rods 18 and 35: another step. i This rotation continues until brush 36 engag'es'a contact 37-=:which 118-isrotated the shaft- '1 is not grounded, at which time magnets 42 and 38 then becomedeenergized. Magnet 42 is made sloWto release its armature, and

therefore it remains". attracted during this rotation of the rod. The'retraction of the armature of magnet 42 causes the crank 20, associated with' the next allotted finder, to engage'thearm 17, so that when the-rod of this allotted finder will be operated. I When the brushes 2 and 3 of the finder switch engage terminals 99' and 98 of the calling line and the side switch moves into position 3, a circuit: is completed from groundedbattery, right-hand winding of relay-70, side-switch arm 105 (third position), conductor 92, brush 3, terminal 98, line conductor 52, telephone apparatus of substation A, conductor 53, terminal 99, brush 2, conductor 91, side-switch arm 104 (third position), left-hand winding of relay 70 to ground; Relay 70: becomes energized and completes a circuit from grounded battery, winding of relay 93," front contact and left-hand armature of relay 70, conductor 94, contact springs 95and' 96 to ground. Since relay 72 is slow releasing, the energizing circuit of the release magnet 12 will be opened at the back contact andleft-hand armature of relay 93 before it is closed'by the deenergization of the 'relay 72.

The releasing of the operated finder switch is as follows: When the calling subscriber at substation A replaces his receiver the circuit of relay 70' is opened, which causes the deenergization of relay 93. A circuit is then completed from grounded battery, winding of release magnet 12, conductor 109, armature and back contact of relay 72, armature and back contact of relay 93, left-hand armature and backcontact of relay 70, conductor 94, contact springs 95 and 96 to ground. Release magnet 12 by attracting its left-hand armature completes a locking circuitfor itself from battery, Wind.- ing of releasemagnet 12, front contact" and left-hand armature of this relay, conductor 94, contact springs 95 and 96 to ground. Release magnet 12 by attracting its right-hand armature removes thevertical holding pawl- 9'from the ratchet 5 and: the rotary pawl 10 from the rotary ratchet 6, thereby allowing the shaft-:1 to return to its normal position, at which. time the locking circuitof relay 12ris opened' at contact. springs 95 and96.=-- f l/Vha'tis claimed is: a 1. In a telephone exchange system, the combination with a plurality of contact banks, a movable shaft individual to each bank, brushes mounted on each shaft and arranged to engage contacts ofsaid contact banksya common driving rod for moving said shafts in one direction, a common driving rod for moving said shafts in .a sec- 0nd direction, emeanscfor placing said conimon rods in operative relation to an idle erative relation to any one of said shafts,

means foroperati'ng .said first mentioned common drlvmg rod .to ralse the selected shaft, and means for subsequently operating I said second common driving rod to rotate said selected shaft.

:3. In a telephone exchange system-,the combination with a plurality of movable shafts, a common driving rod for moving said shafts vertically, a common driving rod for rotating said shafts, means for rotating said rods together to position them inoperative relation toany one of said :shafts, means for'rotating said first'mentioned common driving rod to raise the selected shaft,

and means for subsequently moving said second mentioned common driving rodlongitudinally to rotate said selected shaft.

4:. In atelephone system, the combination of a plurality of contact banks, a mova'ble shaft for each bank, a driving mechanism common :to saidzshafts, means for operating said mechanism step-by-step 'to drive said shafts in one direction, means for operating said mechanism step-by-step ,to drive said shafts in a second direction, and brushes carried by-said shafts arrangedto cooperate with the contact banks.

5. In atelcphone system,'the combination of a plurality of contact banks, a movable shaft for each bank, a driving mechanism commonto said shafts, means for "operating said mechanism step-bystepto driveYsaid shafts vertically, means for operating said mechanism step-by-step to rotate said. shafts, and brushes carried by each shaft arranged to cooperate with the contact banks.

6. In a telephone='syst em,=the combination of a plurality of contact banks, .a movable shaft for each bankxprovided with a. set of brushes, a common driving mechanism for saidshafts, means for allotting said mechanism to one of :said :shafts, andmeans ;for operating the mechanism step-by-step to drive the brushes of :the allotted shaft in two different planes into engagement with the contacts of the-bank.

7. In a telephone system, the combination of a plurality ofcontact banks,a movable shaft for each bank provided with a set of brushes, a common driving 'mechanism for said shafts, means for allotting said mechanism to one of said shafts, and

means for ioperating the mechanism stepby-;step :to drive the brushes of the allotted shaft in two planes at right angles to each other for engaging-theicontacts [of the individual. contact bank.

8. In a telephone exchange system, the combination with a plurality of contact banks, a movable shaft individual to each bank, vbrushes mounted on said shaft and arranged to engage contacts of :said contact bank, a common driving mechanism for tselectmg and lifting and rotating any one, of

asaidsha'fts, whereby the brushes of-said-selected shaft aremoved into engagement with any contactof said contact banks.

In a telephone exchange system, the combination with ;a :plurality of contact arranged to engage contacts ofsaid contact banks, a common driving mechanism for lifting and rotating any one of said shafts,

and means for placing said driving :mecha nism into operative relation to an'idleshaft, whereby the brushes of said selected shaft are :moved .into engagement with any contact of1said contact banks.

10. In :a telephone exchange system, the combination with a plurality of contact banks, contacts :movable in two "directions at right angles to each :other, said movable contacts individual to each bank and arranged to engage :the contacts thereof, mechanical driving ,means common to said movable contacts and adapted to automatically selectand operate any one of said movable contacts individually. 7

11. In a telephone exchange system, the combination with a plurality of contact banks, contacts movable in'two planes, said contacts individual :to each bank and arranged to'engage the contacts thereof, driv- 'ing'means common to said movable contacts and adapted to automatically select and operate any one of the movable contacts in- .dividually.

- '12. In a telephone exchange system, the combination with a plurality of contact banks, contacts movable in two planes-and at right-angles to each other, said contacts individual to each bank and arranged to engage the 'contacts thereof, mechanical drivingmeans commonto' said movable contacts and adapted to automaticallyselect and operate any one 'of said movable contacts individually.

13. In a "telephone system, the combination of' a plurality of contactbankaa movable shaft individual :to each bank, a stepby-step operated rod common to said shafts for operating them in afirst movement, a step-iby-step operated rod common to said shafts for operating .themin a-second movement, and brushes carried by each shaft for engaging said contact banksbanks, a movable shaft individual to each :bank,fbrushes ,mounted on each shaft and 14. In a telephone system, the combination of a plurality of contact banks, a movable shaft for each contact bank, a rod common to said shafts, means for rotating said rod step-by-step to drive said shafts in a first movement, a second rod common to the movable shafts, means for operating said second rod longitudinally in a step-by-step manner to drive said shafts in a second movement, and brushes carried on said shafts for engagement with the contact banks.

15. In a telephone exchange system, the combination with a plurality of contact banks, a movable shaft individual to each bank, brushes mounted on each shaft and arranged to engage contacts of said contact banks, a common driving mechanism for moving said shaft in one direction, a common driving mechanism for moving said shaft in a second direction, means for placing said common driving mechanisms in operative relation to an idle shaft, whereby the brushes of said selected shaft are moved into engagement with any contact of said contact banks.

16. In a telephone system, the combination of a plurality of contact banks, a movable shaft for each contact bank, a member common to all said shafts, means for operating said member in a step-by-step movement to select one of the movable shafts, means for operating said member in a rotary step-by-step movement to drive the selected shaft in its first movement, means for operating said member in a longitudinal step-by-step movement to drive said shaft in its second movement, and brushes carried by each shaft for engagement with the contact banks.

In witness whereof I hereunto subscribe my name this 13th day of July, A. D. 1917.

CHARLES L. GOODRUM. 

